Open Access Highly Accessed Study protocol

British randomised controlled trial of AV and VV optimization (“BRAVO”) study: rationale, design, and endpoints

Zachary I Whinnett1*, S M Afzal Sohaib1, Siana Jones1, Andreas Kyriacou1, Katherine March1, Emma Coady1, Jamil Mayet1, Alun D Hughes2, Michael Frenneaux3, Darrel P Francis1 and On behalf of the BRAVO Investigators

Author Affiliations

1 International Centre for Circulatory Health, National Heart and Lung Institute, Imperial College London, 59-61 North Wharf Road, London W2 1LA, UK

2 Institute of Cardiovascular Sciences, University College London, Gower Street, London WC1E 6BT, UK

3 Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK

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BMC Cardiovascular Disorders 2014, 14:42  doi:10.1186/1471-2261-14-42

Published: 3 April 2014



Echocardiographic optimization of pacemaker settings is the current standard of care for patients treated with cardiac resynchronization therapy. However, the process requires considerable time of expert staff. The BRAVO study is a non-inferiority trial comparing echocardiographic optimization of atrioventricular (AV) and interventricular (VV) delay with an alternative method using non-invasive blood pressure monitoring that can be automated to consume less staff resources.


BRAVO is a multi-centre, randomized, cross-over, non-inferiority trial of 400 patients with a previously implanted cardiac resynchronization device. Patients are randomly allocated to six months in each arm. In the echocardiographic arm, AV delay is optimized using the iterative method and VV delay by maximizing LVOT VTI. In the haemodynamic arm AV and VV delay are optimized using non-invasive blood pressure measured using finger photoplethysmography. At the end of each six month arm, patients undergo the primary outcome measure of objective exercise capacity, quantified as peak oxygen uptake (VO2) on a cardiopulmonary exercise test. Secondary outcome measures are echocardiographic measurement of left ventricular remodelling, quality of life score and N-terminal pro B-type Natriuretic Peptide (NT-pro BNP). The study is scheduled to complete recruitment in December 2013 and to complete follow up in December 2014.


If exercise capacity is non-inferior with haemodynamic optimization compared with echocardiographic optimization, it would be proof of concept that haemodynamic optimization is an acceptable alternative which has the potential to be more easily implemented.

Trial registration NCT01258829

Heart failure; Cardiac resynchronization therapy; Optimization